Air and water supply system for endoscopes

ABSTRACT

The present invention provides a system for endoscopes which can supply air and water according to each application by regulating air and water flow rates independently. Although air and water may be supplied with one pump, the present invention controls air and water flow rates separately by using an air supply pump and water supply pump and by controlling a plurality of open-close valves installed, for example, on atmospheric escape pipes. The air channel and water channel are connected, for draining, by a first connecting pipe. If the air supply pump is used also for water supply and the water supply pump is used also for air supply, it is possible to supply air and water at a high flow rate fast enough even for high-speed water injection. If a fixed flow rate is used for a specified time at the start, specific operations can be simplified.

BACKGROUND OF THE INVENTION

This application claims the priority of Japanese Patent Application Nos.10-89403 and 10-89404 filed on Mar. 17, 1998, Nos. 10-100097, 10-100098and 10-100099 filed on Mar. 27, 1998 which are incorporated herein byreference.

1. Field of the Invention

The present invention relates to an air and water supply system forendoscopes, and more particularly, to an arrangement for flow control ofair and water supply through air feed tubes and water feed tubesinstalled in endoscopes.

2. Description of the Prior Art

Endoscopes are conventionally provided with air feed tubes, water feedtubes, etc. through which air and water (liquid) are supplied to the tipof the endoscope to clean the viewing window (objective lens surfaces)at the tip or remove water-drops from it as well as to inflate a bodycavity such as the stomach by the air sent into the body of the subjectunder observation. After use, endoscopes are cleaned and drained throughthe water feed tubes before storage.

FIG. 12 shows the configuration of a solenoid valve unit of aconventional endoscope. The water feed tube 2A and air feed tube 3A onthe endoscope side are connected to the solenoid valve unit 1. Thesolenoid valve unit 1 comprises a water feed tube 2B, solenoid valve Vafor controlling the opening and closing of the water feed tube 2B, airfeed tube 3B, and solenoid valve Vb for controlling the opening andclosing of the air feed tube 3B, wherein the water feed tube 2B isconnected to a feed water tank 4 through a water feed tube 2C.

The solenoid valve unit 1 also contains an air and water supply pump 5,which is connected with the air feed tube 3B and a tube (air feed tube)for water supply 3C, which in turn is connected to the feed water tank 4through a tube 3D. Furthermore the pump 5 is connected with anatmospheric escape pipe 6, which is equipped with a solenoid valve Vc.The control switch for air/water supply is installed, for example, onthe operating section of the endoscope.

In the above configuration, when the air/water supply switch is notactuated, only the solenoid valve Vc remains open and the air sent fromthe pump 5 is released to the atmosphere through the atmospheric escapepipe 6. When the air/water supply switch is manipulated to supply water,the solenoid valve Va opens and the solenoid valves Vb and Vc close,allowing water to be supplied from the feed water tank 4 to theendoscope through the water feed tubes 2C, 2B, and 2A. When it ismanipulated to supply air, the solenoid valve Vb opens and the solenoidvalves Va and Vc close, allowing air to be supplied through the air feedtubes 3B and 3A.

BRIEF SUMMARY OF THE INVENTION OBJECT OF THE INVENTION

The conventional air and water supply systems of endoscopes are not ableto regulate flow rates (quantities of flow per unit time): they controlonly the on/off operation of air/water supply. They are not capable ofproviding optimum air/water (liquid) supply individually according toapplication. Although the system in FIG. 12 described above is capableof adjusting the flow rates of air and water by changing the supply airpressure (capacity) of the pump 5 itself, it has a problem that isimpossible to control air supply and water supply separately becausechanging the supply pressure of the pump 5 for air flow control willalso change the flow rate of water.

For example, shooting out water at a relatively high flow rate (in thestate of a large quantity of water per unit time) produces good resultswhen cleaning the viewing window, whereas for subsequent drying, it isbetter to inject air at a relatively low flow rate, which will eliminatetiny droplets on the objective lens surfaces. Also, when inflating abody cavity such as the stomach (pneumoperitoneum) to apply anendoscope, it is necessary to feed air, taking into consideration thecondition of the patient. Therefore, it is desirable if air and watercan be supplied at a proper flow rate to suit the specific purposes ofindividual procedures. Besides, changing the supply pressure of the pump5 in FIG. 12 between air supply and water supply may obstruct proceduresbecause of time lags.

Furthermore, the endoscope is drained through the water feed tube 2A andair feed tube 3B after use, but there is a disadvantage that the supplyair pressure during draining depends on the capacity of the pump 5,making optimum draining impossible.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above problems. Theobject of the present invention is to provide an air and water supplysystem for endoscopes that makes it possible to control air flow andwater flow rates independently and supply air and water according toeach application.

On the other hand, endoscopes have a flush water inlet port and aninjection water inlet port installed on a operating section or the like.That is, the flush water inlet port is connected to the water channel ofthe endoscope. And water supplied through the flush water inlet portunder high pressure with a syringe or the like can remove a high levelof contamination from the objective lens surfaces of the viewing window.Also, an injection channel is installed in the endoscope to inject waterto the object of observation. It is connected with the injection waterinlet port installed on the operating section or the like. A liquid suchas physiological saline is supplied through the injection water inletport with a syringe or the like to remove foreign matters which wouldobstruct observation or treatment by adhering to objects underobservation.

However, high-speed water injection and lens surface flushing, which arecarried out by the use of accessories such as a syringe from the flushwater inlet port and injection water inlet port installed on theoperating section, involve complicated operations. Besides, injectionwith a syringe requires skill and experience of the physician. Moreover,these operations require a fast and ample flow of water, whichconventional pumps cannot provide.

Another object of the present invention is to provide an air and watersupply system for endoscopes that will allow high-speed water injectionand lens surface flushing to be performed with simple switch operations.

Furthermore, the air and water supply system for endoscopes shown inFIG. 12 employ flexible tubing made of polyvinyl chloride (PVC) or thelike for the water feed pipe 2A and air feed pipe 3A which connect thesolenoid valve unit 1 with, for example, the light source fitted to theendoscope. And it has a problem that these flexible pipes (2A and 3A)may deform during air or water supply, changing the flow rate andfailing to dry the lens surface of the viewing window sufficiently.

That is, the diameters of the water feed pipes 2 and the like used inthe endoscope increase with approach to the solenoid valve unit 1, forexample, the channel diameter inside the endoscope being approximately 1mm, the tube diameter in the cable being approximately 2 mm, and thediameters of the above-mentioned flexible connecting pipes (2A and 3A)being approximately 5 mm. The walls of the flexible pipes are subject tosome internal pressure. Thus the flexible pipes (2A and 3A) expand underthis pressure during air or water supply, changing the flow rate at thestart or end of air or water supply.

Furthermore, after supplying water to the lens surfaces to clean theviewing window, the pressure produced by the expanded connecting pipe 6Creturning to the original shape will cause a small amount of water toleak from the nozzle at the distal end of the endoscope, resulting inpoor water removal.

Still another object of the present invention is to provide an air andwater supply system for endoscopes that can prevent changes in the flowrate and correct insufficient water removal by suppressing the expansionof the connecting pipes between the endoscope and channel control unit.

To attain the above objects, the present invention is characterized bycomprising a pump for supplying air and water to the distal end throughthe air and water channels, a plurality of open-close valves installedon the air channel, water channel, and atmospheric escape channelconnected to the pump, and a flow control section for specifying the airflow rate in the air channel and water flow rate in the water channelindependently by controlling these valves. The flow control sectionallows the physician to vary the air flow rate while keeping the waterflow rate constant.

According to the above described present invention, it is possible toset the air flow rate and water flow rate to different values, forexample, by dividing the atmospheric escape pipe into a plurality ofbranch pipes and installing a solenoid valve in each of the branchpipes. For example, closing both solenoid valves installed in twoatmospheric escape pipes will provide a High flow rate and closing onlyone of them will provide a Low flow rate. It is possible to switch theair flow rate between the High and Low setting while keeping the waterflow rate at the High setting. This will make it possible to controlboth air and water flow rates through simple installation of solenoidvalves in atmospheric escape pipes, eliminating the need to installseparate means of control for air and water supplies, thus simplifyingthe configuration of the system.

Another aspect of the present invention is characterized by comprisingan air channel, a water channel, an air supply pump, a water supply pumpfor supplying water independently of the air supply pump, and acontrolling section for controlling the air supply pump and the watersupply pump separately to regulate the air flow rate and water flowrate.

This aspect of the present invention comprises a first connecting pipeconnecting the air channel and the water channel as well as anopen-close valve for controlling the opening and closing of the firstconnecting pipe, of which the controlling section can supply air to atleast the air channel.

It also comprises a second connecting pipe for connecting the watersupply pump to the water channel to supply air as well as an open-closevalve for controlling the opening and closing of the second connectingpipe, wherein the controlling section can use two pumps to supply air tothe water channel.

According to the present invention, since independent air and watersupply pumps are employed, their capacities can be selected separatelyto suit the purposes of air supply and water supply. The flow controlmeans can also be employed separately for air supply and water supply.This makes it possible to specify the air flow rate and water flow rateper unit time individually according to application. The use of thefirst connecting pipe and its open-close valve allows air to be suppliedto the water feed tube by the air supply pump at the optimum pressurefor draining. Since two pumps can be used together, for example, tosupply air to the water feed tube, and the intensity of air supply canbe selected according to the condition of draining in this case.

Moreover, this aspect of the present invention can comprise a thirdconnecting pipe for connecting the air supply pump to the water channelto supply water as well as an open-close valve for controlling theopening and closing of the third connecting pipe, wherein thecontrolling section can use two pumps to supply water to the waterchannel.

It also comprises an injection channel, apart from the water channel,for injecting water to objects under observation, the injection channelbeing connected to the third connecting pipe to allow water to besupplied to the injection channel with two pumps.

According to this aspect of the present invention, if the air supplypump is connected, for example, to the water feed tube through the thirdconnecting pipe and its open-close valve, both air and water supplypumps can be used to secure the force and quantity of water supplynecessary to flush the lens surfaces. Advantageously, the air supplypump can also be connected through a connecting pipe and open-closevalve to the injection channel installed apart from the water channel,to secure the force and quantity of water supply necessary forhigh-speed water injection by using both air and water supply pumps.

Still another aspect of the present invention comprises a channel forsupplying air and water to the distal end, flow control means forcontrolling the flow rates of the air and water supply through thischannel variably, a control switch for selecting the flow rate to becontrolled by the flow control means and for performing the air or watersupply, and a control section which controls the flow control means soas to supply air or water at a predetermined fixed flow rate for aspecified time after the air supply or water supply operation is startedby the control switch and then enable any flow rate specified by thecontrol switch.

According to this aspect of the present invention, the flow controlmeans incorporating, for example, multiple pairs of an atmosphericescape pipe and its open-close valve allows air supply and water supplyto be controlled in two steps—High and Low—or any number of steps.Supposing that the High water flow setting and Low air flow setting aremost desirable when cleaning the objective lens surfaces of the viewingwindow, the fixed flow rate of water supply is preset at High and thatof air supply is preset at Low. Accordingly, when water supply isstarted, water is always supplied at the High flow rate for the firstseveral seconds, and then it is supplied at the selected flow rate. Onthe other hand, when air supply is started, air is always supplied atthe Low flow rate for the first several seconds, and then it is suppliedat the selected flow rate. It is possible to limit the use of a fixedflow rate to either air supply or water supply.

Yet another aspect of the present invention is characterized in that theconnecting pipe between the endoscope-side air or water feed tube andthe corresponding tube on the side of the channel control unit is aflexible pipe, which is equal or superior to the air or water feed tubesinside the endoscope in terms of resistance to deformation caused byinternal pressure.

This connecting pipe can be made by coating the outer surface of a softtube with reinforcing material to protect the soft tube againstdeformation while maintaining its flexibility. Possible reinforcingmaterials include heat-shrinkable tubing, meshes, and adhesive coils.This aspect of the present invention can make the connecting pipe equalor superior to the air or water feed tubes inside the endoscope in termsof resistance to deformation, preventing expansion of the connectingpipe due to air or water pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the overall configuration of an endoscopewith the application of the air and water supply system according to thefirst embodiment of the present invention;

FIG. 2 is an explanatory drawing showing the relationship between air orwater supply operations and solenoid valve operations according to thefirst embodiment of the present invention;

FIG. 3 is a drawing illustrating the configuration of the system on theendoscope side according to the second embodiment of the presentinvention;

FIG. 4 is a diagram illustrating the configuration of the system on thesolenoid unit side according to the second embodiment of the presentinvention;

FIG. 5 is an explanatory drawing showing the relationship between air orwater supply operations and solenoid valve operations according to thesecond embodiment of the present invention;

FIG. 6 is a diagram illustrating the configuration of the system on thesolenoid valve unit side according to the third embodiment of thepresent invention;

FIG. 7 is a drawing illustrating the configuration of the air and watersupply system on the endoscope side according to the fourth embodimentof the present invention;

FIG. 8 is a diagram illustrating the configuration of the solenoid valveunit to be connected to the endoscope according to the fourth embodimentof the present invention;

FIG. 9 is an explanatory drawing showing the relationship between air orwater supply operations and solenoid valve operations according to thefourth embodiment of the present invention;

FIG. 10 is an explanatory drawing showing the relationship between airor water supply operations and solenoid valve operations according tothe fifth embodiment of the present invention;

FIG. 11 is a diagram illustrating the configuration of the solenoidvalve unit to be connected to the endoscope according to the sixthembodiment of the present invention; and

FIG. 12 is a diagram illustrating the configuration of a solenoid valveunit of a conventional endoscope.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

FIG. 1 shows the configuration of the air and water supply system forendoscopes according to the first embodiment of the present invention.As shown in the figure, the endoscope (electronic endoscope) 10 has awater feed tube 12A, an air feed tube 13A, and a suction tube 14Arunning from a distal end 10A to a operating section 10B. The tip of thedistal end 10A is fitted with a detachable cap 15, on which a nozzle orthe like are installed to supply air and water to the viewing window(lens surfaces of an objective optical system).

The operating section 10B contains an air/water supply switch 16, whichis a two-step switch, a suction switch 17, and a picture button 18, asshown in FIG. 1. The operation control signals of the switches 16 and 17are supplied to a solenoid valve unit 20. A water feed tube 12B and anair feed tube 13B are installed in a cable to connect the operatingsection 10B and the solenoid valve unit 20. A channel unit 10C isreleasably attached to the backside of the operating section 10B. Thefolded portion formed when a channel unit 10C is attached connects thewater feed tube 12A with the water feed tube 12B, and the air feed tube13A with the air feed tube 13B.

The channel unit 10C is fitted with a suction tube 14B extending to thesolenoid valve unit 20. A suction tube 14B bifurcates and one of thebranches is fitted with a forceps inlet port 21.

The solenoid valve unit 20 contains a water feed tube 12C with asolenoid valve V11 (open-close valve), an air feed tube 13C with asolenoid valve V13, a pump 23, and an auxiliary air feed tube 13D with asolenoid valve V12 for supplying air from the pump 23 to the water feedtube 12B. The auxiliary air feed tube 13D and a solenoid valve V12 areused to drain the water feed tubes 12A and 12B on the endoscope side.

The water feed tube 12C is connected through a water feed tube 12D to afeed water tank 24, which is connected through a tube 13F with a tube(air feed tube) 13E, which in turn is connected to the pump 23. Each ofthe air feed tubes 13C, 13D, and 13E is provided with a check valve 25to prevent water and the like from flowing backward into the air feedtubes (13C to 13E) in the solenoid valve unit 20, thus keeping theirinside from being contaminated.

The pump 23 is connected with atmospheric escape pipes 26A and 26B whichmerge into one pipe before connecting to the pump 23 and which areequipped with solenoid valves V14 and V15. The solenoid valve unit 20also contains a controlling section 28 for controlling theabove-mentioned solenoid valves V11 to V15 (and to V17), a power supplyunit 29, etc. The closing and opening of the solenoid valves V14 and V15regulate the flow rates of air supply and water supply separately.

Since the supply air pressure of the pump 23 varies depending on whetherone or both of the solenoid valves V14 and VI5 are closed, the flowrates of air supply and water supply can be changed by changing theOpen/Close pattern of the solenoid valves V14 and V15.

Furthermore, the solenoid valve unit 20 contains a suction tube 14Cequipped with a solenoid valve V16 and connected to the suction tube14B. The suction tube 14C is connected to a suction tank 30, which isalso connected with a suction pump not shown in the figure. Also, thesuction tube 14C is connected with an atmospheric escape pipe 31 andsolenoid valve V17.

The control panel of the solenoid valve unit 20 is equipped with a flowcontrol switch 33, which can be used to control the flow rate of airsupply in two steps (High and Low). This flow control can also beperformed with a control switch on the operating section 10B. Forexample, an air flow control switch may be provided separately from awater flow control switch as a two-step switch or as a control switchthat allows stepwise control by sensing the pressing force of switchmanipulation.

For example, this control switch will employ a pressure sensitive diode,piezoresistive micromachined silicon element, or the like as a pressuresensor, which will be pushed by an final control element (pushbutton)moved up and down (or a sensor which detects the length of an operatingstroke). This arrangement will make it possible to regulate the air flowrate by controlling the opening and closing of the solenoid valves V14and V15 according to the stepwise pressing force of the final controlelement.

This embodiment has the configuration just described, where theactuation of the solenoid valve unit 20 actuates the pump 23 and opens,for example, the solenoid valves V14 and V15 (or it is also possible toopen only one of them), releasing the air in the pump 23 into theatmosphere (V17 is opened on the suction side). To supply air or water,the physician should operate the flow control switch 33 on the solenoidvalve unit 20 and the air/water supply switch 16 on the operatingsection 10B of the endoscope. The Open/Close states of the solenoidvalves V11 to V15 at this time are shown in FIG. 2.

Specifically, pressing the first step of the air/water supply switch 16with the flow control switch 33 set at High opens only the solenoidvalve V13 and closes the other solenoid valves V11, V12, V14, and V15,as shown in FIG. 2, Column (A). Since both atmospheric escape pipes 26Aand 26B are closed, air is supplied through the air feed tubes 13C to13A at the higher flow rate. For example, air can be sent to a bodycavity such as the stomach in a short time.

On the other hand, pressing the second step of the air/water supplyswitch 16 under the above-mentioned condition opens only the solenoidvalve V11 and closes the other solenoid valves V12 to V15, as shown inFIG. 2, Column (C). Since both atmospheric escape pipes 26A and 26B areclosed also in this case, water is supplied through the water feed tubes12C to 12A at the higher flow rate. This mode can be used, for example,to remove contamination from the viewing window with good results bysupplying water at a relatively high flow velocity.

Now, pressing the first step of the air/water supply switch 16 with theflow control switch 33 set at Low opens the solenoid valves V13 and V15and closes the other solenoid valves V11, V12, and V14, as shown in FIG.2, Column (B). Since only one atmospheric escape pipe 26A is closed, airis supplied at the lower flow rate. This mode can be used, for example,to dry the viewing window after the above-mentioned cleaning with goodresults by supplying air at a relatively low flow velocity.

When the suction switch 17 shown in FIG. 1 is pressed; the solenoidvalve V16 opens and the solenoid valve V17 closes, suction is performedthrough the suction tubes 14C to 14A, and filth and the like are suckedthrough the distal end 10A and discharged to the suction tank 30.

With the present system, the water feed tubes 12A and 12B can be drainedby the use of the air feed tube 13D and solenoid valve V12.Specifically, when only the solenoid valve V12 is opened and the othersolenoid valves V11 and V13 to V15 are closed, air is sent from the pump23 through the water feed tubes 12B and 12A to the distal end, drainingthe given channel. This draining operation is performed to clean thechannel after using the endoscope.

In the above example, the flow rate of air supply was changed in twosteps, but the flow rate may be changed in several steps for air supplyand water supply separately.

As discussed above, the first embodiment allows air and water to besupplied at the flow rate suitable for a specific purpose. Besides, asflow control means, solenoid valves are installed in the atmosphericescape pipes connected to the pump to change the flow rate of the fluidcoming out of the tubes concerned, eliminating the need to provideseparate means for controlling air supply and water supply, and thussimplifying the configuration.

Second Embodiment

FIG. 3 and FIG. 4 show the configuration of the air and water supplysystem for endoscopes according to the second embodiment of the presentinvention. The configuration on the endoscope side is almost the same asthat shown in FIG. 1. As shown in FIG. 3, however, this embodiment haswater feed tubes 12 equipped with a flush water inlet port 19, which isused to feed air/water by the use of a syringe or the like when theobjective lens surfaces are heavily contaminated.

As shown in FIG. 4, the solenoid valve unit 70 contains a water feedtube 12C equipped with a solenoid valve V1 (open-close valve) andconnected to the above-mentioned water feed tube 12B. The water feedtube 12C is connected to a feed water tank 24 through a water feed tube12D. The solenoid valve unit 70 also contains a water supply pump 73, towhich the feed water tank 24 is connected through tubes (air feed tubes)24A and 24B. The water supply pump 73 is connected with atmosphericescape pipes 75A and 75B which merge into one pipe before connecting tothe water supply pump 73 and which are equipped with solenoid valves V2and V3, whose opening and closing actions control water supply in twosteps (High and Low). That is, since the supply air pressure of thewater supply pump 73 varies depending on whether one or both of thesolenoid valves V2 and V3 are closed, the flow rate of air supply to thefeed water tank 24 can be changed by selecting whether to close one orboth of the solenoid valves.

On the other hand, an air feed tube 13C and solenoid valve V4 areconnected between the endoscope-side air feed tube 13B and an air supplypump 77. In this embodiment, the air supply pump 77 has a capacity (airsupply pressure) different from that of the water supply pump 73, but,of course, it may have the same capacity. The air supply pump 77 is alsoconnected with atmospheric escape pipes 78A and 78B which merge into onepipe before connecting to the air supply pump 77 and which are equippedwith solenoid valves V5 and V6, whose opening and closing actions cancontrol air supply in two steps (High and Low).

A first connecting pipe 80 extends from the air feed tube 13C in theoutput section of the air supply pump 77 to the water feed tube 12C. Itis fitted with a solenoid valve V7 and supplies the air for draining thewater feed tubes 12B and 12A with the help of the solenoid valve V7. Theair feed tubes, 13C, 74A, and 80 are all fitted with a respective checkvalve 81 to prevent water and the like from flowing backward into theair feed tubes 13C, 74A, and 80.

Furthermore, the solenoid valve unit 70 contains a suction tube 14Cequipped with a solenoid valve V8 and connected to the suction tube 14B.The suction tube 14C is connected to a suction tank 30. Also, thesuction tube 14C is connected with an atmospheric escape pipe 84 andsolenoid valve V9. The opening and closing of the solenoid valves V1 toV9 are controlled form a controlling section 86.

The control panel of the solenoid valve unit 70 is equipped with flowcontrol switches: an air flow control switch 88 for switching the airflow rate between High and Low, and a water flow control switch 89 forswitching the water flow rate between High and Low, in this example. Adrain switch 90 is also installed on the control panel.

This flow control can also be performed with a control switch on theoperating section 10B described earlier. As described with respect tothe first embodiment, a water flow control switch may be providedseparately from an air flow control switch as a two-step switch or as acontrol switch that allows stepwise control using a pressure sensor bysensing the pressing force of switch manipulation. This arrangement willmake it possible to regulate the air flow or water flow rate bycontrolling the opening and closing of the solenoid valves V2 and V3, orV5 and V6 according to the stepwise pressing force of the final controlelement.

This embodiment has the configuration just described, where the air flowcontrol switch 88 or water flow control switch 89, and the air/watersupply switch 16 on the operating section 10B of the endoscope aremanipulated for air or water supply. The Open/Close states of thesolenoid valves V1 to V7 at this time are shown in FIG. 5. Moreprecisely, the actuation of the solenoid valve unit 70 actuates thewater supply pump 73 and air supply pump 77, opens the solenoid valvesV2 and V3, for example, (or it is also possible to open only one ofthem), and opens the solenoid valves V5 and V6, as shown in FIG. 5,Column (A), releasing the air in the pumps 73 and 77 into the atmosphere(V9 is opened on the suction side).

Then, pressing the first step of the air/water supply switch 16 with theair flow control switch 88 set at High opens the solenoid valve V4 onthe air feed tube 13C and closes the flow control solenoid valves V5 andV6, as shown in FIG. 5, Column (B). Since both atmospheric escape pipes88A and 88B are closed, air is supplied through the air feed tubes 13Cto 13A at the higher flow rate. For example, air can be sent to a bodycavity such as the stomach in a short time.

On the other hand, pressing the second step of the air/water supplyswitch 16 with the water flow control switch 89 set at High opens thesolenoid valve V1 on the water feed tube 12C and closes the flow controlsolenoid valves V2 and V3 as shown in FIG. 5, Column (D). Since bothatmospheric escape pipes 75A and 75B are closed also in this case, wateris supplied through the water feed tubes 12C to 12A at the higher flowrate. This mode can be used, for example, to remove contamination fromthe viewing window with good results by supplying water at a relativelyhigh flow velocity.

Now, pressing the first step of the air/water supply switch 16 with theair flow control switch 88 set at Low opens the solenoid valve V4 on theair feed tube 13C and closes only the flow control solenoid valve V6 asshown in FIG. 5, Column (C). Since only one atmospheric escape pipe 78Bis closed, air is supplied at the lower flow rate. This mode can beused, for example, to dry the viewing window after the above-mentionedcleaning with good results by supplying air at a relatively low flowrate.

On the other hand, pressing the second step of the air/water supplyswitch 16 with the water flow control switch 89 set at Low opens thesolenoid valve V1 on the water feed tube 12C and closes only the flowcontrol solenoid valve V2 as shown in FIG. 5, Column (E). Since only oneatmospheric escape pipe 75A is closed also in this case, water issupplied at the lower flow rate.

Pressing the drain switch 90 of the solenoid valve unit 70 (for example,after using the endoscope) opens the solenoid valve V7 of the firstconnecting pipe 80 and closes the flow control solenoid valves V5 and V6as shown in FIG. 5, Column (F). Consequently, air is sent from the airsupply pump 77 through the water feed tubes 12C, 12B, and 12A to thedistal end, draining and cleaning the given channel. In this way, airand water supply can be controlled separately at the flow rates suitablefor a specific purpose.

When the suction switch 17 shown in FIG. 1 is pressed, the solenoidvalve V8 opens and the solenoid valve V9 closes, suction is performedthrough the suction tubes 14C to 14A, and filth or the like is suckedthrough the distal end 10A and discharged to the suction tank 30.

Third Embodiment

FIG. 6 shows the configuration of the system according to the thirdembodiment of the present invention. This embodiment employs two pumpsto drain the above-mentioned water feed tubes 12. It is almost the sameas the second embodiment, but differs from it in that in a solenoidvalve unit 91, a second connecting pipe 92 coming from the tube 74Aconnected to the water supply pump 73 is connected to the output side ofthe first connecting pipe 80 and fitted with a solenoid valve V10.

In this third embodiment, when a drain switch 90 of the solenoid valveunit 91 is pressed, a solenoid valve V7 of the first connecting pipe 80and solenoid valve V10 of the second connecting pipe 92 are opened andflow control solenoid valves V5, V6, V2, and V3 are closed. Any of thesolenoid valves V2, V3, V5, and V6 can be opened to reduce flow rates.This makes it possible to drain the water feed tubes 12C, 12B, and 12Aby supplying air with both air supply pump 77 and water supply pump 73,allowing the tubes to be drained at a higher air flow rate than in thecase of the second embodiment.

Although the above example explained only two-step flow control, anynumber of steps may be used actually. Also, although the first andsecond connecting pipes 80 and 92 were used to supply air to the waterfeed tubes 12, they can be configured to supply water to the air feedtubes 13.

As described above, the second and third embodiments broaden the choicesof air flow rates by the use of the two pumps 73 and 77 and simplify thedraining of water feed tubes by using the first and second connectingpipes 80 and 92.

Fourth Embodiment

FIGS. 7 and 8 show the configuration of the system according to thefourth embodiment of the present invention. As shown in FIG. 7, theendoscope 10 has injection pipes 11A and 11B running from the distal end10A to the cable to inject water to objects under observation. Itsoperating section 10B is equipped with an injection switch 118. The restof the configuration on the endoscope side is the same as the otherembodiments described earlier. The operation control signals of theinjection switch 118 are supplied to the solenoid valve unit 120 shownin FIG. 8.

As is the case with the solenoid valve unit in FIG. 4, the solenoidvalve unit 120 in FIG. 8 contains a water feed tube 12C equipped with asolenoid valve V21 (which serves as an open-close valve), andatmospheric escape pipes 75A and 75B which merge into one pipe toconnect to the air supply pump 73 and which are equipped with solenoidvalves V22 and V23, whose opening and closing actions can control watersupply in two steps (High and Low).

On the other hand, an air feed tube 13C equipped with a solenoid valveV24 is connected to an air supply pump 77, which may have a capacity(air supply pressure) different from or equal to that of the watersupply pump 73 in this embodiment. The air supply pump 77 is also, asflow control means, connected with atmospheric escape pipes 78A and 78Bwhich merge into one pipe before connecting to the air supply pump 77and which are equipped with solenoid valves V25 and V26, whose openingand closing actions can control air supply in two steps (High and Low).

A first connecting pipe 80 extends from the air feed tube 13C in theoutput section of the air supply pump 77 to the water feed tube 12C. Itis fitted with a solenoid valve V27 and supplies the air for drainingthe water feed tubes 12B and 12A with the help of the solenoid valveV27.

The injection pipe 11B in FIG. 7 is connected with an injection pipe 11Cand a solenoid valve V28, then the injection pipe 11C is connectedthrough the water feed tubes 12C and 12D to a feed water tank 24.Furthermore, a third connecting pipe 132 extends from the output sectionof the air supply pump 77 to a tube 74A on the side of the water supplypump 73. It is fitted with a solenoid valve V29 and they together makeit possible to use the air supply pump 77 together with the water supplypump 73 for high-speed water injection or lens surface flushing.

Besides, the solenoid valve unit 120 has a suction tube 14C connectedwith a solenoid valve V30 and an atmospheric escape pipe 84 connectedwith a solenoid valve V31 and contains a controlling section 136 and thelike for controlling the opening and closing of the solenoid valves V21to V31. The air flow control switch 88 and the like on the control panelare the same as those for the second embodiment.

The fourth embodiment has the configuration just described and theOpen/Close states of the solenoid valves V21 to V29 are shown in FIG. 9.The actuation of the solenoid valve unit 120 actuates the water supplypump 73 and air supply pump 77, opens the solenoid valves V22 and V23,for example, and opens the solenoid valves V25 and V26, as shown in FIG.9, Column (A), releasing the air in the pumps 73 and 77 into theatmosphere.

Then, pressing the first step of the air/water supply switch 16 with theair flow control switch 88 set at High opens the solenoid valve V24 onthe air feed tube 13C and closes the flow control solenoid valves V25and V26, as shown in FIG. 9, Column (B). Since both atmospheric escapepipes 88A and 88B are closed consequently, pneumoperitoneum can beperformed at a high flow rate in a short time.

On the other hand, pressing the second step of the air/water supplyswitch 16 with the water flow control switch 89 set at High opens thesolenoid valve V21 on the water feed tube 12C and closes the flowcontrol solenoid valves V22 and V23 as shown in FIG. 9, Column (D).Since both atmospheric escape pipes 75A and 75B are closed also in thiscase, cleaning of the viewing window and the like can be performed at ahigh flow rate.

Now, pressing the first step of the air/water supply switch 16 with theair flow control switch 88 set at Low opens the solenoid valve V24 onthe air feed tube 13C and closes only the flow control solenoid valveV26 as shown in FIG. 9, Column (C). Since only one atmospheric escapepipe 88B is closed consequently, the viewing window can be dried aftercleaning at a low flow rate.

On the other hand, pressing the second step of the air/water supplyswitch 16 with the water flow control switch 89 set at Low opens thesolenoid valve V21 on the water feed tube 12C and closes only the flowcontrol solenoid valve V22 as shown in FIG. 9, Column (E). Thus, wateris supplied at the lower flow rate.

Pressing the injection switch 118 on the operating section 10B opens thesolenoid valve V28 of the injection pipe 11C and the solenoid valve V29of the third connecting pipe 132 while closing the flow control solenoidvalves V29, V23, V25, and V26, as shown in FIG. 9, Column (F). Sincewater is supplied from the feed water tank 24 not only by the watersupply pump 73, but also by the air supply pump 77, deposits and thelike can be removed from the viewing window by very powerful waterinjection through the injection pipes 11B and 11A.

In this example, water is injected automatically at the maximum flowrate, but the system may be configured to regulate this flow rate with aseparate switch, the air flow control switch 88, or the water flowcontrol switch 89. For example, if the flow control switches 88 and 89are used, the injection force and water quantity can be varied dependingon whether one or both of the switches are set to Low.

Pressing the drain switch 40 of the solenoid valve unit 120 (forexample, after using the endoscope) opens the solenoid valve V27 of thefirst connecting pipe 80 and closes the flow control solenoid valves V25and V26 (V22 and V23 are open) as shown in FIG. 9, Column (G).Consequently, air is sent from the air supply pump 77 through the waterfeed tubes 12C, 12B, and 12A to the distal end, draining and cleaningthe given channel. In this way, air and water supply can be controlledseparately, using the flow rates suitable for a specific purpose.

This embodiment can also use the two pumps 73 and 77 to feed water andflush the lens surfaces. Specifically, a flush switch can be installedat any desired place and then this flush switch and the controllingsection 136 can be manipulated to open the solenoid valve V21 on thewater feed tube 12C and solenoid valve V29 on the third connecting pipe132 and close the flow control solenoid valves V22, V23, V25, and V26,allowing the two pumps 73 and 77 to feed water at a high flow velocitythrough the water feed tubes 12B and 12A. This will make it possible toremove a large amount of stubborn dirt from the objective lens surfacesof the viewing window.

As described above, the fourth embodiment allows high-speed waterinjection and lens surface flushing to be performed with simple switchoperation while providing the necessary injection force and waterquantity.

Fifth Embodiment

The configuration of the fifth embodiment is the same as that of thesecond embodiment shown in FIGS. 3 and 4 except that the controllingsection (86) installed in the solenoid valve unit 70 performs controlactions different from those of the second embodiment. Moreparticularly, the controlling section (86) enables the flow ratesselected by the air flow control switch 88 and water flow control switch89, but it uses a predetermined fixed flow rate for a specified time atthe start when the air/water supply switch 16 is pressed and operated.

This embodiment fixes the water flow rate at High and the air flow rateat Low (the fixed flow rates are specified as required according to thesupply air pressures of the pumps 73 and 77 as well as the number ofcontrol steps) to suit the air supply or water supply for cleaning ofthe viewing window and uses these flow rates for the first few seconds(2 to 5 seconds), and then switches to the flow rates selected by theflow control switches 88 and 89. This embodiment will be useful insituations, such as air supply for cleaning of the viewing window, whereoperation at fixed flow rates are desirable because it will betroublesome to adjust flow rates if the air or water flow rate can beselected freely.

FIG. 10 shows the operation of the solenoid valves in the fifthembodiment. Pressing the second step of the air/water supply switch 16with the water flow control switch 89 in FIG. 4 set at Low opens thesolenoid valve V1 on the water feed tube 12C and closes the flow controlsolenoid valves V2 and V3 for the first few seconds, as shown in FIG.10, Column (B). Both atmospheric escape pipes 75A and 75B of the watersupply pump 73 are closed to supply water through the water feed tubes12C to 12A at the higher flow rate for the first few seconds. Thus,contamination can be removed fairly well from the viewing window bywater supplied at a relatively high flow velocity. Then, as shown inFIG. 10, Column (C), the flow control solenoid valve V3 opens (the othersolenoid valves remain as they are), leaving only one 75A of theatmospheric escape pipes closed. Thus, water is supplied at the lowerflow rate.

Then, pressing the first step of the air/water supply switch 16 with theair flow control switch 88 set at High opens the solenoid valve V4 onthe air feed tube 13C (V2, V3, and V5 remain open) and closes only oneflow control solenoid valve V6 (V1 remains closed) for the first fewseconds, as shown in FIG. 10, Column (D). Consequently, only oneatmospheric escape pipes 78B of the air supply pump 77 are closed tosupply air through the air feed tubes 13C to 13A at the lower flow rate.This mode can be used to dry the viewing window after theabove-mentioned cleaning with good results by supplying air at arelatively low flow rate.

Subsequently, as shown in FIG. 10, Column (E), the flow control solenoidvalve V5 as well as both atmospheric escape pipes 78A and 78B are closedto supply air at the selected High flow rate. This mode allows air to besent to a body cavity such as the stomach in a short time. Thus, whenperforming pneumoperitoneum, air is sent first at the optimum flow ratefor drying and then at the optimum flow rate for pneumoperitoneum. Whenonly drying the objective lens surfaces, what is needed is to cancel thesetting of the air/water supply switch 16 in a few seconds and there isno need to select a flow rate setting.

Thus, advantageously, this embodiment simplifies the cleaning of theviewing window: even if a different flow rate has been selected for airor water supply, air or water is always fed at the optimum flow rateduring cleaning of the viewing window, which is a frequently-performedoperation.

Although in the above example, the fixed initial flow rate was set atHigh for water supply and at Low for air supply, it can be specifiedfreely taking various conditions into consideration. It may be set atLow for water supply and at High for air supply, conversely. Or thespecification of initial flow rate can be limited only to air supply.

As described above, according to the fifth embodiment, in variablecontrol of air or water supply which involves air or water supply forcleaning of the viewing window, air or water is fed automatically at apredetermined flow rate, eliminating the trouble of regulating the flowrate.

Sixth Embodiment

FIG. 11 shows the configuration of the air and water supply system forendoscopes according to the sixth embodiment of the present invention.The cable 214C in FIG. 11 is identical to the cables used in theendoscopes according to the other embodiments. It is connected through aconnector block 228 to a light source unit 203. Then it connects a lightguide (not shown) to the light source in the light source unit 203. Thecable 214C contains a water feed tube 216B and air feed tube 217B. Thesetubes are made of polytetra-fluoroethylene (known as the trade nameTeflon), etc. such that they will not expand under water or airpressure.

A signal wire contained in the cable 214C is connected to a processorunit 205 through a signal cable 204 branching off from the connectorblock 228. The connector block 228 is connected with a solenoid valveunit 224 through a water supply connecting pipe 216C and air supplyconnecting pipe 217C made of soft tubes (polyvinyl chloride or thelike).

The solenoid valve unit 224 contains a water feed tube 216D equippedwith a solenoid valve Va and connected to the connecting pipe 216C. Theother end of the water feed tube 216D is connected to a feed water tank24. The solenoid valve unit 224 also contains a pump 229, which isconnected to the feed water tank 24 through a tube 230. On the otherhand, the connecting pipe 217C is connected to an air feed tube 217Dequipped with a solenoid valve Vb. The other end of the air feed tube217D is connected to the pump 229, which is also connected with anatmospheric escape pipe 231 equipped with a solenoid valve Vc.

Furthermore, the solenoid valve unit 224 contains a suction tube 218Cequipped with a solenoid valve Vd and connected to a suction tube 218B.The suction tube 218C is also connected with an atmospheric escape pipe233 and a solenoid valve Ve.

The water supply connecting pipe 216C and air supply connecting pipe217C are coated with reinforcing material, heat-shrinkable tubes 234Aand 234B, which, after being fitted over the connecting pipes 216C and217C, respectively, are heated to enhance adhesion to the outer surfacesof the connecting pipes while maintaining flexibility. After coating,the tubes 234A and 234B can suppress expansion of the soft (PVC)connecting pipes 216C and 217C.

Adhesive coils may be used instead of the heat-shrinkable tubes 234A and234B to coat the connecting pipes 216C and 217C. Or the connecting pipes216C and 217C themselves may be formed into wire-reinforced flexibletubes. The use of reinforcing material can protect the connecting pipes216C and 217C from deformation or expansion under air or water pressure.

It is also possible to make connecting pipes 216C and 217C ofpolytetrafluoroethylene (fluororesin) as is the case with endoscope-sidewater feed tubes 216A and 216B and air feed tubes 217A and 217B, and settheir wall thickness properly in order to make the deformation due tointernal pressure approximately equal to that of the tubes 216A, 216B,217A, and 217B.

The sixth embodiment has the configuration just described above, wherethe solenoid valve unit 224 performs air supply and water supply in asimilar fashion to the system shown in FIG. 12. In doing that, theconnecting pipe 216C is subjected to a certain water pressure, and theconnecting pipe 217C to a certain air pressure. However, theheat-shrinkable tubes 234A and 234B suppress expansion of the connectingpipes 216C and 217C. Therefore, the air flow rate and water flow rateremain stable and the objective lens surfaces of the viewing window aredried properly after cleaning.

What is claimed is:
 1. An air and water supply system for endoscopescomprising: a pump for supplying air and water to the distal end of anendoscope through an air channel and water channel; a plurality ofopen-close valves installed on the air channel, water channel, and anatmospheric escape channel connected to said pump; and a flow controlsection which sets the air flow rate in said air channel and water flowrate in said water channel per unit time individually by controllingsaid open-close valves.
 2. The air and water supply system forendoscopes according to claim 1, wherein said atmospheric escape channelconnected to said pump is provided with a plurality of open-close valvesfor changing the rate of flow from said atmospheric escape channel andwherein said flow control section regulates flow rates by controllingsaid open-close valves.
 3. The air and water supply system forendoscopes according to claim 1, wherein said flow control sectionperforms such control as to vary said air flow rate with said water flowrate kept constant.
 4. An air and water supply system for endoscopesaccording to claim 1, comprising: a connecting pipe for connecting saidair channel and said water channel; and an open-close valve for openingand closing said connecting pipe, wherein said flow control sectionsupplies air to said water channel.
 5. An air and water supply systemfor endoscopes according to claim 1, comprising: flow control means forvariably controlling the flow rate of said air or water supply throughsaid channel; a control switch for selecting the flow rate to becontrolled by said flow control means and for performing said air supplyor water supply; and a control selection which controls said flowcontrol means so specified time after said air supply or water supplyoperation is started by said control switch.
 6. An air and water supplysystem for endoscopes according to claim 1, comprising: a flexibleconnecting pipe which connects an endoscope-side tube and acontrol-unit-side tube and which is equal or superior to the air orwater channel inside the endoscope in terms of resistance to deformationcaused by internal pressure.
 7. The air and water supply system forendoscopes according to claim 6, wherein said connecting pipe is made bycoating the outer surface of a soft tube with reinforcing material toprotect the soft tube against deformation while maintaining itsflexibility.